For the cream :
1/4 l milk
3 egg yolks
70 g sugar
50 cl whipping cream
300 g bitter chocolate
For the chocolate sponge cake :
125 g sugar
20 g flour
20 g cocoa powder
40 g butter melted in a bain-marie
1. Start by preparing the sponge cake by mixing the sugar and eggs with an electric whisk until the mixture is smooth. Quickly stir in the flour with a wooden spoon and then the cocoa.
2. At the last moment add the melted butter and stop stirring as soon as it is incorporated. Butter and flour a 30 cm diameter baking tin, pour in the batter and bake for 30 minutes in a medium oven (gas mark 6).
3. Prepare the pastry cream. At the same time, put the chopped chocolate in a pan and melt it in the oven. When the chocolate is melted, pour it into a large bowl and mix it with the warm custard.
4. In another bowl, whip the cream and mix it with the custard.Cut the sponge cake in three parts thickness.
Pour half of the cream over the first sponge cake, spreading it evenly with a spatula.
5. Place the second sponge cake on top and pour the remaining cream. Cover with the last sponge cake. Leave to set for 6 hours in the fridge before serving.